Related bugs

Related FAQ:

I sympathize with your frustration, it is a common gotcha that we're working on fixing. The problem is Graphite can not "accurately" aggregate your datapoints unless you tell it what aggregation method to use for which metrics, and historically there has not been a good way to do that. There is a very active branch under development (https://code.launchpad.net/~chrismd/+junk/graphite-megacarbon) that addresses this issue among several others by refactoring the carbon configuration model. In the new model we generalize storage-schemas.conf to consist of rules that can apply arbitrary metadata to your metrics, so in addition to specifying the retention configuration you will also be able to specify the desired aggregation method using regexes, etc to specify which metrics use which method. This branch is still in flux but it is going to be in the next release (in fact the next release will primarily consist of the work already done on this branch). There is also a new API provided by the webapp in 0.9.9 that lets you get/set metadata for metrics programmatically but that is more intended for one-off changes rather than sweeping "handle all these metrics this way" type of changes that the storage rules will provide.

Whisper can't support multiple aggregation methods but Ceres could, and the new storage-rules.conf would make configuring it possible. We'd have to extend Ceres' rollup aggregation plugin to support that.

Regarding the carbon aggregation, you can configure as many aggregation rules as you'd like, so you could compute multiple aggregates from the same set of input metrics. Only sum and avg are implemented currently but adding more functions would be pretty trivial.